U.S. patent number 9,126,789 [Application Number 14/332,710] was granted by the patent office on 2015-09-08 for image forming apparatus.
This patent grant is currently assigned to Canon Kabushiki Kaisha. The grantee listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Ryuji Hamasaki, Hirofumi Hori, Shunsuke Okazaki.
United States Patent |
9,126,789 |
Hori , et al. |
September 8, 2015 |
Image forming apparatus
Abstract
The present invention provides an image forming apparatus that
can facilitate a replacement of a sheet feeding portion. When a
detecting portion detects that a sheet feeding cassette is mounted,
a controller controls a driving portion in such a manner as to lift
a sheet supporting plate for the mounted sheet feeding cassette.
When the detecting portion detects that a sheet feeding cassette is
mounted, the controller controls a driving portion in such a manner
as not to lift a sheet supporting plate for the mounted sheet
feeding cassette in the case where it is determined that a sheet
feeding cassette nearest a feeding roller of the mounted sheet
feeding cassette is drawn or detached.
Inventors: |
Hori; Hirofumi (Numazu,
JP), Hamasaki; Ryuji (Zhongshan, CN),
Okazaki; Shunsuke (Mishima, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
N/A |
JP |
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Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
52342957 |
Appl.
No.: |
14/332,710 |
Filed: |
July 16, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150021847 A1 |
Jan 22, 2015 |
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Foreign Application Priority Data
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Jul 22, 2013 [JP] |
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2013-151521 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H
1/28 (20130101); B65H 3/44 (20130101); B65H
1/266 (20130101); B65H 7/02 (20130101); B65H
2511/20 (20130101); B65H 2511/515 (20130101); B65H
2601/324 (20130101); B65H 2601/321 (20130101); B65H
2405/332 (20130101); B65H 2511/515 (20130101); B65H
2220/01 (20130101); B65H 2220/11 (20130101); B65H
2511/20 (20130101); B65H 2220/02 (20130101); B65H
2220/11 (20130101) |
Current International
Class: |
B65H
1/26 (20060101); B65H 3/44 (20060101); B65H
1/28 (20060101); B65H 7/02 (20060101) |
Field of
Search: |
;271/9.11,9.01,9.02 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2000-264485 |
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Sep 2000 |
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JP |
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2004-256287 |
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Sep 2004 |
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JP |
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Primary Examiner: Cicchino; Patrick
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. A sheet feeding apparatus configured to feed a sheet to an image
forming unit, comprising: a frame of the sheet feeding apparatus; a
first sheet storage unit including a first sheet stacking portion
on which a sheet is stacked, the first sheet storage unit being
drawable with respect to the frame; a second sheet storage unit
including a second sheet stacking portion on which a sheet is
stacked, the second sheet storage portion being drawable with
respect to the frame and being disposed above the first sheet
storage unit; a first sheet feeding unit configured to feed the
sheet stacked on the first sheet stacking portion; a second sheet
feeding unit configured to feed the sheet stacked on the second
sheet stacking portion; a first lift unit configured to lift the
first stacking portion; a first detecting unit configured to detect
that the first sheet storage unit is mounted at a first position on
the frame; a second detecting unit configured to detect that the
second sheet storage unit is mounted at a second position on the
frame; a first conveyance path provided in the frame and configured
to guide the sheet fed by the first feeding unit to the image
forming unit; a second conveyance path provided in the frame and
configured to guide the sheet fed by the second feeding unit to the
image forming unit; a controller configured to control the first
lift unit, wherein the controller controls the first lift unit such
that the first lift unit restricts lifting of the first stacking
portion in a case where the first detecting unit detects that the
first sheet storage unit is mounted at the first position on the
frame in a state that the second detecting unit does not detect
that the second sheet storage unit is mounted at the second
position on the frame, and wherein the first sheet feeding unit
includes a roller, the roller being at a position where detaching
of the roller from the frame is allowable in a state that the
second storage unit is drawn from the second position with respect
to the frame, and detaching of the roller from the frame is
allowable through a space formed by the second storage unit being
drawn from the second position with respect to the frame.
2. The sheet feeding apparatus according to claim 1, wherein the
controller controls the first lift unit such that the first lift
unit lifts the sheet stacking portion in accordance with the second
detection unit detecting that the second sheet storage unit is
mounted on the second position on the frame in a state that the
lifting of the first stacking portion has been restricted.
3. The sheet feeding apparatus according to claim 1, wherein the
first sheet storage unit is drawable with respect to the frame in a
direction perpendicular to a direction in which the sheet is fed by
the first sheet feeding unit and the second sheet storage unit is
drawable with respect to the frame in a direction perpendicular to
a direction in which the sheet is fed by the second sheet feeding
unit.
4. The sheet feeding apparatus according to claim 1, wherein the
first sheet storage unit and the second sheet storage unit are
vertically arranged.
5. The sheet feeding apparatus according to claim 1, wherein the
second sheet storage unit is disposed immediately above the first
sheet storage unit.
6. The sheet feeding apparatus according to claim 1, wherein the
controller controls the first lift unit such that the first lift
unit does not lift the first sheet stacking portion in a case where
the first detecting unit detects that the first sheet storage unit
is mounted on the first position on the frame in a state that the
second detecting unit does not detect that the second sheet storage
unit is mounted on the second position on the frame.
7. The sheet feeding apparatus according to claim 1, wherein the
second sheet stacking portion lowers in accordance with the second
sheet storage unit being drawn from the second position.
8. The sheet feeding apparatus according to claim 1, further
comprising a second lift unit configured to lift the second
stacking portion, wherein the controller controls the second lift
unit.
9. The sheet feeding apparatus according to claim 8, wherein the
first lift unit and the second lift unit include at least one
driving source.
10. The sheet feeding apparatus according to claim 8, wherein the
first lift unit lifts the first sheet stacking portion to a
position where the sheet can be fed by the first sheet feeding unit
and the second lift unit lifts the second sheet stacking portion to
a position where the sheet can be fed by the second sheet feeding
unit.
11. The sheet feeding apparatus according to claim 1, wherein the
second conveyance path guides the sheet fed by the second sheet
feeding unit to the first conveyance path.
12. The sheet feeding apparatus according to claim 1, wherein the
controller controls the first lift unit such that the first lift
unit lifts the first stacking portion in a case where the first
detecting unit detects that the first sheet storage unit is mounted
at the first position on the frame in a state that the second
detecting unit detects that the second sheet storage unit is
mounted at the second position on the frame, and wherein the
controller controls the first lift unit such that the first lift
unit restricts lifting of the first stacking portion in a case
where the first detecting unit detects that the first sheet storage
unit is mounted at the first position on the frame in a state that
the second detecting unit does not detect that the second sheet
storage unit is mounted on the second position on the frame.
13. A sheet feeding apparatus configured to feed a sheet to an
image forming unit comprising: a frame of the sheet feeding
apparatus; a first sheet storage unit including a first sheet
stacking portion on which a sheet is stacked, the first sheet
storage unit being drawable from a first position with respect to
the frame; a second sheet storage unit including a second sheet
stacking portion on which a sheet is stacked, the second sheet
storage unit being drawable from a second position with respect to
the frame and disposed above the first sheet storage unit; a first
sheet feeding unit configured to feed the sheet stacked on the
first sheet stacking portion; a second sheet feeding unit
configured to feed the sheet stacked on the second sheet stacking
portion; a first lift unit configured to lift the first stacking
portion; and a controller configured to control the first lift
unit, wherein the first sheet feeding unit includes a roller
positioned at a position where detaching of the roller from the
frame is allowable in a state that the second storage unit is drawn
from the second position with respect to the frame, wherein the
controller controls the first lift unit such that the first lift
unit restricts lifting of the first stacking portion in a case
where the first sheet storage unit is mounted at the first position
on the frame in a state that the second sheet storage unit is not
mounted at the second position on the frame, and wherein detaching
of the roller from the frame is allowable through a space formed by
the second sheet storage unit being drawn from the second position
with respect to the frame.
14. The sheet feeding apparatus according to claim 13, wherein the
first sheet storage unit is drawable with respect to the frame in a
direction perpendicular to a direction in which the sheet is fed by
the first sheet feeding unit and the second sheet storage unit is
drawable with respect to the frame in a direction perpendicular to
a direction in which the sheet is fed by the second sheet feeding
unit.
15. The sheet feeding apparatus according to claim 13, wherein the
first sheet storage unit and the second sheet storage unit are
vertically arranged.
16. The sheet feeding apparatus according to claim 13, wherein the
second sheet storage unit is disposed immediately above the first
sheet storage unit.
17. The sheet feeding apparatus according to claim 13, wherein the
second sheet stacking portion lowers in accordance with the second
sheet storage unit being drawn from the second position.
18. The sheet feeding apparatus according to claim 13, further
comprising a second lift unit configured to lift the first sheet
stacking portion, wherein the controller controls the second lift
unit.
19. The sheet feeding apparatus according to claim 18, wherein the
first lift unit and the second lift unit include at least one
driving source.
20. The sheet feeding apparatus according to claim 18, wherein the
first lift unit lifts the first sheet stacking portion at a
position where the sheet can be fed by the first sheet feeding unit
and the second lift unit lifts the second sheet stacking portion at
a position where the sheet can be fed by the second sheet feeding
unit.
21. The sheet feeding apparatus according to claim 13, further
comprising a first conveyance path provided in the frame and
configured to guide the sheet fed by the first feeding unit to the
image forming unit; a second conveyance path provided in the frame
and configured to guide the sheet fed by the second feeding unit to
the image forming unit.
22. The sheet feeding apparatus according to claim 21, wherein the
second conveyance path guides the sheet fed by the second feeding
unit to the first conveyance path.
23. The sheet feeding apparatus according to claim 13, further
comprising a first detecting unit configured to detect that the
first sheet storage unit is mounted on the first position on the
frame; and a second detecting unit configured to detect that the
second sheet storage unit is mounted on the second position on the
frame.
24. The sheet feeding apparatus according to claim 23, wherein the
controller controls the first lift unit such that the first lift
unit does not lift the first stacking portion in a case where the
first detecting unit detects that the first sheet storage unit is
mounted on the first position of the apparatus main body in a state
that the second detecting unit does not detect that the second
sheet storage unit is mounted on the second position of the
apparatus main body.
25. The sheet feeding apparatus according to claim 23, wherein the
controller controls the first lift unit such that the lift unit
lifts the sheet stacking portion in accordance with the second
detection unit detecting that the second sheet storage unit is
being mounted at the second position on the frame in a state that
the lifting of the first stacking portion has been restricted.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus and,
more particularly, to the replacement of a sheet feeding
(supplying) unit in the case where a plurality of sheet storage
units is provided in a main body of an image forming apparatus.
2. Description of Related Art
In some of conventional image forming apparatuses such as a copying
machine and a printer, a plurality of sheet storage units is
superposed at the lower section of a main body of an image forming
apparatus or is arranged in a lateral direction, so that the number
of sheets that can be fed is increased, and further, sheets having
different sizes can be used.
A sheet feeding cassette serving as a sheet storage unit is
provided with a sheet supporting plate serving as a sheet stacking
member that can be moved in a vertical direction in which a sheet
is stacked. Moreover, on the side of the main body of the image
forming apparatus are provided a lifting and lowering mechanism for
lifting and lowering the sheet supporting plate and a feeding
roller constituting a sheet feeding unit for feeding the sheet
stacked on the sheet feeding cassette.
When the sheet feeding cassette is installed in the main body of
the image forming apparatus, the lifting and lowering mechanism
lifts the sheet supporting plate, and thus, the sheet stacked on
the sheet supporting plate is moved to a position at which the
sheet can be supplied/fed by the feeding roller. Thereafter, when
one out of the plurality of sheet feeding cassettes is selected,
the sheet stacked on the selected sheet feeding cassette is
supplied/fed by the feeding roller located above the selected sheet
feeding cassette.
In the meantime, if the feeding roller is degraded due to abrasion
or the like in the conventional image forming apparatus, sheet
feeding performance is deteriorated. Therefore, the feeding roller
need be replaced with a new one periodically or in much abrasion
amount. At this time, in order to facilitate the replacement of the
feeding roller, the feeding roller has been detachably attached to
the main body of the image forming apparatus in the related art
(see Japanese Patent Laid-Open No. 2004-256287). Alternatively, the
feeding roller has been replaced by using a roller replacing tool
(see Japanese Patent Laid-Open No. 2000-264485).
Here, in the case where the feeding roller is configured in a
detachably attachable manner, the sheet feeding cassette need be
detached, and then, the feeding roller need be replaced, since the
feeding roller is disposed above the sheet feeding cassette.
However, in the case where the feeding roller is located at the
lower section of the main body of the image forming apparatus, the
feeding roller cannot be visually recognized even if the sheet
feeding cassette is detached. In this case, a replacement section
is peeped through a clearance produced by detaching the sheet
feeding cassette, and further, a hand need be inserted through the
clearance, followed by replacement of the feeding roller.
On the other hand, in the case where the feeding roller is located
at the lower section of the main body of the image forming
apparatus, a worker need work with his/her eyes under his/her
waist, resulting in poor workability. Moreover, there is a
possibility that the sheet feeding cassette may not be detached in
the case where the sheet feeding cassette has a large capacity. In
this case, a worker need work in the state in which the sheet
feeding cassette is kept drawn, so that it becomes more difficult
to replace the feeding roller because of the hindrance of the
large-capacity cassette to the standing position of a worker.
The present invention has been accomplished in view of the
above-described current circumstances. Therefore, it is desirable
to provide an image forming apparatus, in which a sheet feeding
unit can be readily replaced.
SUMMARY OF THE INVENTION
An image forming apparatus according to the present invention
includes: a plurality of sheet storage portions that has a sheet
stacking portion, which can be lifted and lowered and on which a
sheet is stacked, the plurality of sheet storage portions being
drawably provided in an apparatus main body; a sheet feeding
portion that is disposed above each of the sheet storage portions
and supplies and feeds the sheet stacked on the sheet stacking
portion; a driving portion that lifts the sheet stacking portion in
the sheet storage portion mounted in the apparatus main body to a
position at which the sheet can be supplied and fed by the sheet
feeding portion; a detecting portion that outputs a detection
signal when the sheet storage portion is mounted at a mounting
position inside of the apparatus main body; and a controller that
controls the driving portion in such a manner as to lift the sheet
stacking portion in the sheet storage portion based on the
detection signal output from the detecting portion, wherein the
controller, when one of adjacent sheet storage portions is mounted,
controls the driving portion in such a manner as not to lift the
sheet stacking portion in the one sheet storage portion based on
the detection signal output from the detecting portion in the state
in which the other sheet storage portion is drawn or detached.
Like the present invention, when the sheet storage portion nearest
the sheet feeding portion of the sheet storage portion is drawn or
detached, the sheet stacking portion for the mounted sheet storage
portion is prevented from being lifted, so that the sheet feeding
portion can be readily replaced.
Further features of the present invention will become apparent from
the following description of exemplary embodiments (with reference
to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view illustrating the schematic configuration of a
full-color laser beam printer exemplifying an image forming
apparatus according to an exemplary embodiment of the present
invention.
FIG. 2 is a perspective view illustrating the full-color laser beam
printer.
FIG. 3 is a view explanatory of the configuration of a sheet
feeding device disposed in the full-color laser beam printer.
FIG. 4 is a view explanatory of the configuration of a sheet
feeding cassette disposed in the sheet feeding device.
FIG. 5 is a control block diagram illustrating the full-color laser
beam printer.
FIG. 6 is a view illustrating a state in which the sheet feeding
cassette immediately above a lowermost sheet feeding cassette in
the sheet feeding device is detached from the sheet feeding
device.
FIG. 7 is a flowchart illustrating a sheet feeding operation by the
sheet feeding device and a control operation at the time of the
replacement of a feeding roller.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A detailed description will be given below of an exemplary
embodiment according to the present invention with reference to the
attached drawings. FIG. 1 is a view illustrating the schematic
configuration of a full-color laser beam printer exemplifying an
image forming apparatus according to an exemplary embodiment of the
present invention; and FIG. 2 is a perspective view illustrating
the full-color laser beam printer.
In FIG. 1, a full-color laser beam printer 50 (hereinafter referred
to as a printer) includes a printer main body 51 serving as the
main body of an image forming apparatus (i.e., an image forming
apparatus main body) and an image forming portion 52 for forming an
image on a sheet. The image forming portion 52 is provided with a
laser scanner 55, four process cartridges 56 for forming toner
images of four colors, that is, yellow (Y), magenta (M), cyan (C),
and black (K), an intermediate transfer unit 60, a fixing portion
70, and the like.
The intermediate transfer unit 60 includes: an intermediate
transfer belt 63 stretched across a drive roller 61, a tension
roller 62, and the like; and a primary transfer roller 64 that is
disposed inside of the intermediate transfer belt 63 and abuts
against the intermediate transfer belt 63 at a position facing a
photosensitive drum 57. At a position facing the drive roller 61 at
the intermediate transfer unit 60 is provided a secondary transfer
roller 65 constituting a secondary transfer unit for transferring a
color image formed on the intermediate transfer belt onto a sheet
P. Moreover, the fixing portion 70 is disposed above the secondary
transfer roller 65, and further, above the fixing portion 70 are
disposed a pair 80 of discharge rollers and a double-sided
reversing portion 81.
A sheet feeding cassette 30A on the side of the main body is
detachably attached at the lower section of the printer main body
51. A sheet feeding device 1 detachably provided with a plurality
of sheet feeding cassettes 30a, 30b, and 30c, that is, three in the
present exemplary embodiment, is disposed at the lower section of
the printer main body 51. Each of the printer main body 51 and the
sheet feeding device 1 includes a sheet feeding portion 53 for
feeding the sheet P stored in each of the sheet feeding cassette
30A on the side of the main body and the three sheet feeding
cassettes 30a, 30b, and 30c.
Next, a description will be given of an image forming operation in
the printer 50 such configured as described above. First, when
image information is received from a personal computer or the like,
not illustrated, the surface of the photosensitive drum in each of
the process cartridges 56 is scanned with laser beams emitted from
the laser scanner 55 according to image information on the yellow,
magenta, cyan, and black component colors in the image forming
portion 52. In this manner, the surface of the photosensitive drum
57 that is uniformly charged at a predetermined polarity and
potential by a charger 58 is sequentially exposed to the laser
beams, so that electrostatic latent images of the yellow, magenta,
cyan, and black colors are sequentially formed on the
photosensitive drum in each of the process cartridges 56.
Thereafter, the electrostatic latent images are developed into
visible images with toners of the yellow, magenta, cyan, and black
colors reserved in toner cartridges 54, respectively, by a
development device 59. The toner image of each of the colors formed
on each of the photosensitive drums is sequentially transferred in
superposition on the intermediate transfer belt 63 by a primary
transfer bias applied to the primary transfer roller 64. As a
consequence, the toner images are formed on the intermediate
transfer belt 63.
In parallel to this toner image forming operation, the sheet P
stacked on the sheet feeding cassette 30A on the side of the main
body or the sheet feeding cassette 30a, 30b, or 30c is fed out by
the sheet feeding portion 53, and then, the fed sheet P is conveyed
to a pair 66 of registration rollers. After that, the skew feeding
of the sheet P is corrected by the pair 66 of registration rollers,
and then, the sheet P is conveyed to a secondary transfer unit, at
which the toner images are transferred onto the sheet P at a time
by a secondary transfer bias applied to the secondary transfer
roller 65.
Subsequently, the sheet P having the toner images transferred
thereonto is conveyed to the fixing portion 70, at which the color
toners are melted in mixture with the application of heat and
pressure, so that the toner images are fixed onto the sheet P as a
color image. Thereafter, the sheet P having the color image fixed
thereonto is stacked on a stack tray 4 by the pair 80 of discharge
rollers disposed downstream of the fixing portion 70.
In the meantime, the sheet feeding device 1 is provided with the
sheet feeding cassettes 30 (i.e., 30a to 30c) serving as the
plurality of sheet storage units, as described already, in a
drawable manner in a housing-like device main body 1a. A sheet
supporting plate 5 serving as a sheet stacking unit, on which the
sheet is stacked, is disposed in the sheet feeding cassette 30a in
such a manner as to be pivotal (freely lifted and lowered) manner
in a vertical direction on a shaft 6 as a fulcrum, as illustrated
in FIG. 3. Moreover, the sheet feeding portion 53 is provided with
a feeding roller 10 for feeding the sheet stored in the sheet
feeding cassette 30a and a pair of separation rollers 11a and 11b
for separating the sheets fed one by one by a feeding roller 10.
The feeding roller 10 and the pair of separation rollers 11a and
11b constitute a sheet feeding unit.
Additionally, the sheet feeding cassette 30a includes width
restricting plates 7a and 7b that can be moved in a width direction
perpendicular to a sheet feeding direction so as to restrict the
position of the sheet to be stored, and a rear end restricting
plate 8 that can be moved in the sheet feeding direction so as to
restrict the rear end of the sheet, as illustrated in FIG. 4. When
the sheet is replenished, the sheet feeding cassette 30a is drawn
from the sheet feeding device 1, and then, the width restricting
plates 7a and 7b and the rear end restricting plate 8 are
positioned according to the size of the sheet to be stored.
Thereafter, the sheet is stacked on the sheet supporting plate 5,
and then, the sheet feeding cassette 30a is inserted into the
device main body 1a of the sheet feeding device 1. Here, the sheet
feeding cassettes 30b and 30c arranged under the sheet feeding
cassette 30a also have the same configuration as that of the sheet
feeding cassette 30a, and therefore, their description will be
omitted.
FIG. 5 is a control block diagram illustrating the full-color laser
beam printer according to the present exemplary embodiment. In FIG.
5, a CPU 200 serves as a control unit. To the CPU 200 is connected
a lifting motor M1 serving as a driving unit for lifting each of
the sheet supporting plates 5 for the three sheet feeding cassettes
30a, 30b, and 30c up to a position at which the sheet can be
supplied and fed by the feeding roller 10. Moreover, to the CPU 200
are connected a feeding motor M2 for driving the feeding roller 10
and the pair of separation rollers 11a and 11b, an operation
portion 18 provided with a display (i.e., a monitor), not
illustrated, and the like.
In addition, to the CPU 200 are connected a mounting detecting
sensor 15 for generating a detection signal that allows the CPU 200
to detect whether or not the sheet feeding cassette 30 is mounted,
and a sheet existence detecting sensor 16 for generating a
detection signal that allows the CPU 200 to detect whether or not
the sheet is present on the sheet supporting plate. Moreover, to
the CPU 200 is connected a sheet height detecting sensor 17 for
generating a detection signal that allows the CPU 200 to detect
whether or not an uppermost sheet Pa out of the sheets P stacked on
the sheet supporting plate reaches a position at which the sheet
can be supplied and fed by the feeding roller 10.
In the present exemplary embodiment, a general sensor in which the
movement of a detecting button or a detecting flag in abutment
against the sheet feeding cassette or the sheet turns a photo
interrupter on or off so as to generate a detection signal is used
as each of the sensors. The mounting detecting sensor 15 outputs an
ON signal when the sheet feeding cassette 30 is mounted whereas it
outputs an OFF signal when the sheet feeding cassette 30 is
drawn.
The sheet existence detecting sensor 16 outputs an ON signal in the
case where the sheet is present on the sheet supporting plate
whereas it outputs an OFF signal in the case where the sheet is
absent on the sheet supporting plate. Moreover, the sheet height
detecting sensor 17 outputs an ON signal in the case where the
uppermost sheet Pa is in a predetermined height whereas it outputs
an OFF signal in the case where the uppermost sheet Pa is
positioned lower than the predetermined height.
Incidentally, the plurality of lifting motors M1 may be provided
for lifting and driving the sheet supporting plate 5 for each of
the sheet feeding cassettes 30a to 30c, or the single lifting motor
M1 may selectively lift and drive the sheet supporting plate 5 via
a clutch or the like. In the same manner, the plurality of feeding
motors M2 may be provided for driving each of the sheet feeding
portions 53, or the single feeding motor M2 may selectively drive
each of the sheet feeding portions 53 via a clutch or the like. The
mounting detecting sensor 15, the sheet existence detecting sensor
16, and the sheet height detecting sensor 17 are provided at each
of the sheet feeding cassettes 30a to 30c.
When the sheet feeding cassette 30 is mounted at a mounting
position inside of the device main body, at which the sheet can be
supplied and fed in the sheet feeding device 1, the mounting
detecting sensor 15 outputs the detection signal (i.e., the ON
signal). In response to the detection signal, the CPU 200 drives
the lifting motor M1 so as to lift the sheet supporting plate 5. As
illustrated in FIG. 3, when the sheet supporting plate 5 is lifted,
the CPU 200 stops the drive of the lifting motor M1 based on the
detection signal (i.e., the ON signal) output from the sheet height
detecting sensor 17. At this time, the uppermost sheet Pa out of
the sheets P stacked on the sheet supporting plate 5 is located at
a position at which the sheet can be supplied and fed by the
feeding roller 10. Thereafter, when the operation portion 18
selects any one of the sheet feeding cassettes 30a to 30c, the CPU
200 drives the feeding motor M2 so as to rotate the feeding roller
10 and the pair of separation rollers 11a and 11b positioned above
the selected sheet feeding cassette. In this manner, the sheet can
be supplied and fed from the selected one out of the sheet feeding
cassettes 30a to 30c.
Incidentally, when the sheets are supplied and fed so that no sheet
is present on the sheet supporting plate 5, the CPU 200 allows the
operation portion 18 to display the absence of the sheet on the
display based on the detection signal (i.e., the OFF signal) output
from the sheet existence detecting sensor 16. A user draws the
sheet feeding cassette 30 having no sheet stacked thereon from the
sheet feeding device 1 according to the display so as to replenish
sheets. Here, the sheet supporting plate 5 is normally in the
lifted state immediately before the sheet feeding cassette 30 is
drawn when the sheet feeding cassette 30 is drawn. Therefore, when
the sheet feeding cassette 30 is drawn, the sheet feeding cassette
30 is disconnected from the lifting motor M1, so that the sheet
supporting plate 5 is lowered. When the sheet supporting plate 5 is
lowered, sheets can be easily stored in the sheet feeding cassette
30.
In the meantime, the feeding roller 10 is degraded due to abrasion
or the like, thereby causing the deterioration of sheet feeding
performance. In view of this, the feeding roller 10 is replaced
periodically or in the case where the abrasion amount of the
feeding roller 10 becomes large. In the present exemplary
embodiment, the sheet feeding cassette 30 can be drawn from the
sheet feeding device 1, and further, can be detached therefrom.
When sheets are replenished, the sheet feeding cassette 30 is drawn
on the way, and then, the sheets are replenished. When the feeding
roller 10 is replaced, the sheet feeding cassette 30 is completely
drawn from the sheet feeding device 1, and then, the feeding roller
10 is replaced. Here, according to the configuration of the device,
when the sheet feeding cassette 30 is drawn on the way, a hand may
reach the feeding roller 10. In this case, the sheet feeding
cassette 30 need not be detached.
Next, a description will be given of the case where the feeding
roller 10 is replaced. The feeding roller 10 is replaced by
utilizing a mounting space for the sheet feeding cassette adjacent
thereto. Specifically, the other sheet feeding cassette disposed
above one out of the sheet feeding cassettes, on which the sheet is
supplied and fed by the feeding roller, is drawn, so that the
feeding roller 10 is replaced by utilizing a mounting space for the
other sheet feeding cassette.
For example, when the lowermost feeding roller 10 is replaced, the
sheet feeding cassette 30b right above the lowermost sheet feeding
cassette 30c is detached from the device main body 1a of the sheet
feeding device 1, as illustrated in FIG. 6. Next, the lowermost
sheet feeding cassette 30c is once drawn from the device main body
1a of the sheet feeding device 1, and thereafter, the sheet feeding
cassette 30c is pushed in to be returned to the original mounting
position. In this manner, the lowermost sheet feeding cassette 30c
is slightly drawn, so that the sheet supporting plate 5 and the
lifting motor M1 are disconnected from each other, thus lowering
the sheet supporting plate 5.
And then, even if the lowermost sheet feeding cassette 30c is
mounted again in the device main body 1a, the sheet supporting
plate 5 is kept at the lowered position. In other words, the sheet
feeding cassette 30c is drawn or inserted by slight amount, the
sheet supporting plate 5 can be located at the lower position.
Here, "the sheet feeding cassette right above" signifies the upper
sheet feeding cassette disposed adjacently in the vertical
direction without any sheet feeding cassettes interposed between
the lower sheet feeding cassette and the same.
When the lowermost sheet feeding cassette 30c returns to the
mounting position, the mounting detecting sensor 15 detects the
return. Normally, the CPU 200 drives the lifting motor M1 based on
the detection signal output from the mounting detecting sensor 15,
so as to lift the sheet supporting plate 5. However, the control
for replacing the feeding roller is different from the
above-described control. Specifically, in the case where the sheet
feeding cassette 30c disposed right under the sheet feeding
cassette 30b is drawn or inserted in the state in which the sheet
feeding cassette 30b is kept detached, the CPU 200 does not drive
the lifting motor M1 even if the CPU 200 detects that the sheet
feeding cassette 30c is mounted based on the detection signal
output from the mounting detecting sensor 15.
Consequently, even if the lowermost sheet feeding cassette 30c
returns to the mounting position, the sheet supporting plate 5 is
not lifted, and therefore, the feeding roller 10 to be replaced
cannot be brought into contact with the sheet stacked on the sheet
supporting plate 5. Moreover, since the sheet feeding cassette 30b
nearest and right above the sheet feeding cassette 30c is detached,
the upper section of the feeding roller 10 to be replaced is
released, thereby securing the visibility of a portion to be
replaced.
Subsequently, a sheet feeding operation and a control operation
when the feeding roller 10 is replaced according to the
above-described exemplary embodiment will be described with
reference to a flowchart of FIG. 7. In FIG. 7, a cassette n+1 is
disposed right under a cassette n. Therefore, in the present
exemplary embodiment, the cassette n represents the cassette 30b
serving as a second sheet storage unit whereas the cassette n+1
represents the cassette 30c serving as a first sheet storage unit.
In addition, the sheet supporting plate n+1 serves as a first sheet
stack unit for the sheet feeding cassette 30c.
First, in the case where the feeding roller 10 in the cassette n+1
(i.e., the lowermost sheet feeding cassette 30c) is replaced, the
cassette n (i.e., the sheet feeding cassette 30b) right above the
cassette n+1 is detached, as illustrated in FIG. 6. Next, the
cassette n+1 is drawn and pushed in. The CPU 200 detects that the
cassette n+1 is open, that is, the cassette n+1 is drawn based on
the detection signal (i.e., the OFF signal) output from the
mounting detecting sensor 15 serving as a first detecting unit
(STEP 1).
Thereafter, the CPU 200 detects that the cassette n+1 is closed,
that is, the cassette n+1 is mounted based on the detection signal
(i.e., the ON signal) output from the mounting detecting sensor 15
(STEP 2). Here, the matter (closure) that the cassette is closed
signifies that the cassette is housed inside of the device main
body 1a whereas the matter (open) that the cassette is open
signifies that the cassette is drawn or detached from the device
main body 1a.
Subsequently, the CPU 200 confirms whether or not the cassette n
(i.e., the cassette 30b) is closed based on the detection signal
(i.e., the ON signal) output from the mounting detecting sensor 15
serving as a second detecting unit (STEP 3). Normally, since the
cassette n (i.e., the cassette 3b) is closed (Y in STEP 3), the CPU
200 drives the lifting motor M1 so as to lift the sheet supporting
plate n+1 in the cassette n+1 (STEP 4).
The CPU 200 drives the lifting motor M1 until it detects that the
uppermost sheet Pa on the sheet supporting plate n+1 is lifted up
to a predetermined position at which the sheet can be supplied and
fed by the feeding roller 10 serving as the first sheet feeding
unit in response to the detection signal output from the sheet
height detecting sensor 17. Thereafter, when the CPU 200 detects
that the uppermost sheet Pa is lifted to the predetermined position
at which the sheet can be supplied and fed by the feeding roller 10
(Y in STEP 5), the CPU 200 stops the driving of the lifting motor
M1. In this manner, the sheet supporting plate n+1 is stopped from
being lifted (STEP 6).
Next, the CPU 200 detects whether or not the sheet is stacked on
the sheet supporting plate n+1 based on the detection signal output
from the sheet existence detecting sensor 16 (STEP 7). In the case
where the CPU 200 detects that the sheet is stacked on the sheet
supporting plate n+1 (Y in STEP 7), the CPU 200 transmits a sheet
feeding preparation completion signal of the sheet supporting plate
n+1 to the operation portion 18 (STEP 8), thereby displaying sheet
feeding preparation completion on the display. In contrast, in the
case where the CPU 200 detects that no sheet is stacked on the
sheet supporting plate n+1 (N in STEP 7), the CPU 200 transmits a
sheet absence signal of the sheet supporting plate n+1 to the
operation portion 18 (STEP 9), thereby displaying "no sheet" on the
display.
On the other hand, in the case where the cassette n (i.e., the
cassette 3b) is not closed (N in STEP 3), even if the mounting
detecting sensor 15 detects the mounting of the cassette n+1, no
initial lifting control is performed in STEP 3 to STEP 6, thus
stopping the sheet supporting plate n+1 from being lifted (STEP
10). As a consequence, even if the cassette n+1 is mounted, the
sheet supporting plate n+1 is kept lowered, so that the feeding
roller 10 to be replaced cannot be brought into contact with the
sheet on the sheet supporting plate n+1.
Moreover, since the right above cassette n is detached, a released
space is defined above the feeding roller 10 to be replaced. The
feeding roller can be visually recognized through the space, and
further, the feeding roller can be replaced when a hand is
inserted. Incidentally, when the cassette n is returned after the
feeding roller is replaced, the initial lifting control in STEP 3
to STEP 6, described already, is started so as to lift the sheet
supporting plate n+1 in the cassette n+1, thus preparing for a
sheet feeding operation. In addition, when the cassette n is
returned, the sheet supporting plate serving as the second sheet
stacking unit for the cassette n also is lifted in the same manner,
so that the uppermost sheet on the sheet supporting plate is lifted
up to the position at which the sheet can be supplied and fed by
the feeding roller serving as the second sheet feeding unit.
As described above, in the case where it is detected that the sheet
feeding cassette right above (the feeding roller 10 of) the mounted
sheet feeding cassette is detached, the sheet supporting plate for
the mounted sheet feeding cassette is not lifted in the present
exemplary embodiment. That is to say, the sheet feeding cassette
corresponding to the feeding roller to be replaced is detached or
inserted so as to lower the sheet supporting plate, before the
sheet supporting plate is stopped from being lifted in the present
exemplary embodiment.
In other words, when the first sheet storage unit is mounted, in
the case of the input of the detection signal indicating that the
second sheet storage unit disposed above is drawn or detached, the
sheet stacking unit for the first sheet storage unit is controlled
in such a manner as not to be lifted. In this manner, the space can
be secured in the vicinity of the feeding roller in the state in
which the feeding roller and the sheet do not abut against each
other, resulting in enhancing the visibility and workability of the
feeding roller to be replaced, so as to facilitate the replacement
of the feeding roller.
Incidentally, although the description has been given of the
replacement of the feeding roller in the present exemplary
embodiment, at least one of the pair of separation rollers 11a and
11b constituting the sheet feeding unit may be replaced. That is to
say, at least one of the feeding roller 10 and the pair of
separation rollers 11a and 11b may be replaced.
Moreover, although the description has been given of the plurality
of sheet feeding cassettes superposed in the vertical direction in
the present exemplary embodiment, the present invention is not
limited to this. For example, also in the case where the plurality
of sheet feeding cassettes is arranged in a lateral direction, the
sheet supporting plate for the mounted sheet feeding cassette is
prevented from being lifted in the state in which the right and
left sheet feeding cassettes nearest the feeding roller are
detached, thus producing similar effects.
Additionally, although the description has been given of the case
where the plurality of sheet feeding cassettes is provided in the
sheet feeding device 1 independently of the printer main body 51 in
the present exemplary embodiment, a plurality of sheet feeding
cassettes may be provided in the printer main body 51, thus
producing similar effects.
While the present invention has been described with reference to
exemplary embodiments, it is to be understood that the invention is
not limited to the disclosed exemplary embodiments. The scope of
the following claims is to be accorded the broadest interpretation
so as to encompass all such modifications and equivalent structures
and functions.
This application claims the benefit of Japanese Patent Application
No. 2013-151521 filed on Jul. 22, 2013, which is hereby
incorporated by reference herein in its entirety.
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